I don't know any programming context immune to human errors.
Stuff just breaks. Sometimes I get lucky and the guy before me wrote a cool test that prevents me from having to start a debugger, but the contrary is often the reality. OSS stuff is usually better, but not much better (OS upgrades always break, for example).
> This describes my everyday experience with any language or codebase.
That is horrifying. That should absolutely not be normal. I don't know what you work with normally, but it's clear that we are working in completely different worlds.